Add support for logging with VSOCK (#255)

For more information about VSOCK, see "man vsock"
( https://man7.org/linux/man-pages/man7/vsock.7.html ).

Makes it possible for processes in a virtual machine to log directly in
DLT running on host without setting up a network connection between
guest and host. It is also probably more efficient. Have not done any
performance measurements (not main reason for patch), but no forwarding
is required as when running DLT in a multi-node setup.

When building dlt-daemon for host, WITH_DLT_DAEMON_VSOCK_IPC should be
enabled for daemon to listen on incoming VSOCK requests. Local
communication method between applications and daemon is still determined
with DLT_IPC. When building for guest, WITH_DLT_LIB_VSOCK_IPC should be
enabled and DLT_IPC will be ignored, which will make libdlt open a VSOCK
socket to the deamon for logging messages.

VSOCK can be tested without a virtual machine. Since VMADDR_CID_HOST is
used by libdlt when connecting, see vsock man page, clients can be run
on host to test VSOCK communication.

Some modifications has been done to be able to handle logging through
FIFO pipe and socket in the same build of dlt-daemon:

- dlt_receiver_init/free_unix_socket() is renamed to
  dlt_receiver_init/free_global_buffer() and used for FIFO as well.
  Also fixes memory leak since dlt_receiver_free_unix_socket() was used
  regardless of whether DLT_USE_UNIX_SOCKET was defined or not.

- Pass type to dlt_receiver_init() instead of dlt_receiver_receive().
  And remove preprocessor conditionals for handling
  DLT_CONNECTION_APP_MSG in dlt_daemon_process_user_messages(). Also
  fixes wrong enum type being passed to dlt_receiver_receive() in
  dlt_client.c (DltClient::mode was used as a DltReceiverType enum but
  it is a DltClientMode enum).

- Add a flag to DltDaemonApplication to indicate whether file descriptor
  is "owned" by the DltDaemonApplication or not. When
  dlt_daemon_application_add() is called due to message received on a
  socket, fd is passed as an argument (app does not own fd). For FIFO,
  a per application FIFO is opened (app owns the fd). Also fixes so that
  user handle is reset for both application and all its contexts when
  resetting any. Prevents fd from being used by accident after it has
  been closed.

dlt_mkdir_recursive() is moved to src/daemon since it is only used in
the daemon. Minimizes use of DLT_USE_UNIX_SOCKET_IPC.

Other bugfixes:

- Call DLT_SEM_FREE() if setting socket to O_NONBLOCK fails in
  src/lib/dlt_user.c:dlt_initialize_socket_connection().

- Close socket if dlt_receiver_init() fails in
  src/lib/dlt_user.c:dlt_initialize_socket_connection().

Signed-off-by: Martin Ejdestig <martin.ejdestig@volvocars.com>

1 files changed, 121 insertions, 38 deletions

diff --git a/src/daemon/dlt-daemon.c b/src/daemon/dlt-daemon.c
index cd6e5d9..d4a5e90 100644
--- a/src/daemon/dlt-daemon.c
+++ b/src/daemon/dlt-daemon.c
@@ -50,6 +50,15 @@
 #   include <linux/stat.h>
 #endif
 
+#ifdef DLT_DAEMON_VSOCK_IPC_ENABLE
+#   ifdef linux
+#       include <linux/vm_sockets.h>
+#   endif
+#   ifdef __QNX__
+#       include <vm_sockets.h>
+#   endif
+#endif
+
 #include "dlt_types.h"
 #include "dlt-daemon.h"
 #include "dlt-daemon_cfg.h"
@@ -106,7 +115,7 @@ void usage()
     printf("  -h            Usage\n");
     printf("  -c filename   DLT daemon configuration file (Default: " CONFIGURATION_FILES_DIR "/dlt.conf)\n");
 
-#ifndef DLT_USE_UNIX_SOCKET_IPC
+#ifdef DLT_DAEMON_USE_FIFO_IPC
     printf("  -t directory  Directory for local fifo and user-pipes (Default: /tmp)\n");
     printf("                (Applications wanting to connect to a daemon using a\n");
     printf("                custom directory need to be started with the environment \n");
@@ -143,7 +152,7 @@ int option_handling(DltDaemonLocal *daemon_local, int argc, char *argv[])
     /* default values */
     daemon_local->flags.port = DLT_DAEMON_TCP_PORT;
 
-#ifndef DLT_USE_UNIX_SOCKET_IPC
+#ifdef DLT_DAEMON_USE_FIFO_IPC
     dlt_log_set_fifo_basedir(DLT_USER_IPC_PATH);
 #endif
 
@@ -171,7 +180,7 @@ int option_handling(DltDaemonLocal *daemon_local, int argc, char *argv[])
             strncpy(daemon_local->flags.cvalue, optarg, NAME_MAX);
             break;
         }
-#ifndef DLT_USE_UNIX_SOCKET_IPC
+#ifdef DLT_DAEMON_USE_FIFO_IPC
         case 't':
         {
             dlt_log_set_fifo_basedir(optarg);
@@ -224,7 +233,7 @@ int option_handling(DltDaemonLocal *daemon_local, int argc, char *argv[])
 
     /* switch() */
 
-#ifndef DLT_USE_UNIX_SOCKET_IPC
+#ifdef DLT_DAEMON_USE_FIFO_IPC
     snprintf(daemon_local->flags.userPipesDir, DLT_PATH_MAX,
              "%s/dltpipes", dltFifoBaseDir);
     snprintf(daemon_local->flags.daemonFifoName, DLT_PATH_MAX,
@@ -263,11 +272,11 @@ int option_file_parser(DltDaemonLocal *daemon_local)
     daemon_local->flags.loggingMode = DLT_LOG_TO_CONSOLE;
     daemon_local->flags.loggingLevel = LOG_INFO;
 
-#ifdef DLT_USE_UNIX_SOCKET_IPC
+#ifdef DLT_DAEMON_USE_UNIX_SOCKET_IPC
     n = snprintf(daemon_local->flags.loggingFilename,
                  sizeof(daemon_local->flags.loggingFilename),
                  "%s/dlt.log", DLT_USER_IPC_PATH);
-#else
+#else /* DLT_DAEMON_USE_FIFO_IPC */
     n = snprintf(daemon_local->flags.loggingFilename,
                  sizeof(daemon_local->flags.loggingFilename),
                  "%s/dlt.log", dltFifoBaseDir);
@@ -298,14 +307,14 @@ int option_file_parser(DltDaemonLocal *daemon_local)
     strncpy(daemon_local->flags.ctrlSockPath,
             DLT_DAEMON_DEFAULT_CTRL_SOCK_PATH,
             sizeof(daemon_local->flags.ctrlSockPath) - 1);
-#ifdef DLT_USE_UNIX_SOCKET_IPC
+#ifdef DLT_DAEMON_USE_UNIX_SOCKET_IPC
     snprintf(daemon_local->flags.appSockPath, DLT_IPC_PATH_MAX, "%s/dlt", DLT_USER_IPC_PATH);
 
     if (strlen(DLT_USER_IPC_PATH) > DLT_IPC_PATH_MAX)
         fprintf(stderr, "Provided path too long...trimming it to path[%s]\n",
                 daemon_local->flags.appSockPath);
 
-#else
+#else /* DLT_DAEMON_USE_FIFO_IPC */
     memset(daemon_local->flags.daemonFifoGroup, 0, sizeof(daemon_local->flags.daemonFifoGroup));
 #endif
     daemon_local->flags.gatewayMode = 0;
@@ -626,7 +635,7 @@ int option_file_parser(DltDaemonLocal *daemon_local)
                         }
                     }
 
-#ifndef DLT_USE_UNIX_SOCKET_IPC
+#ifdef DLT_DAEMON_USE_FIFO_IPC
                     else if (strcmp(token, "DaemonFifoGroup") == 0)
                     {
                         strncpy(daemon_local->flags.daemonFifoGroup, value, NAME_MAX);
@@ -728,7 +737,43 @@ int option_file_parser(DltDaemonLocal *daemon_local)
     return 0;
 }
 
-#ifndef DLT_USE_UNIX_SOCKET_IPC
+#ifdef DLT_DAEMON_USE_FIFO_IPC
+static int dlt_mkdir_recursive(const char *dir)
+{
+    int ret = 0;
+    char tmp[PATH_MAX + 1];
+    char *p = NULL;
+    char *end = NULL;
+    size_t len;
+
+    strncpy(tmp, dir, PATH_MAX);
+    len = strlen(tmp);
+
+    if (tmp[len - 1] == '/')
+        tmp[len - 1] = 0;
+
+    end = tmp + len;
+
+    for (p = tmp + 1; ((*p) && (ret == 0)) || ((ret == -1 && errno == EEXIST) && (p != end)); p++)
+        if (*p == '/') {
+            *p = 0;
+            ret = mkdir(tmp, S_IRWXU);
+            *p = '/';
+        }
+
+
+
+    if ((ret == 0) || ((ret == -1) && (errno == EEXIST)))
+        ret = mkdir(tmp, S_IRWXU);
+
+    if ((ret == -1) && (errno == EEXIST))
+        ret = 0;
+
+    return ret;
+}
+#endif
+
+#ifdef DLT_DAEMON_USE_FIFO_IPC
 static DltReturnValue dlt_daemon_create_pipes_dir(char *dir)
 {
     int ret = DLT_RETURN_OK;
@@ -811,7 +856,7 @@ int main(int argc, char *argv[])
 
     PRINT_FUNCTION_VERBOSE(daemon_local.flags.vflag);
 
-#ifndef DLT_USE_UNIX_SOCKET_IPC
+#ifdef DLT_DAEMON_USE_FIFO_IPC
 
     /* Make sure the parent user directory is created */
     if (dlt_mkdir_recursive(dltFifoBaseDir) != 0) {
@@ -979,7 +1024,7 @@ int dlt_daemon_local_init_p1(DltDaemon *daemon, DltDaemonLocal *daemon_local, in
 
 #endif
 
-#ifndef DLT_USE_UNIX_SOCKET_IPC
+#ifdef DLT_DAEMON_USE_FIFO_IPC
 
     if (dlt_daemon_create_pipes_dir(daemon_local->flags.userPipesDir) == DLT_RETURN_ERROR)
         return DLT_RETURN_ERROR;
@@ -1174,7 +1219,7 @@ static int dlt_daemon_init_serial(DltDaemonLocal *daemon_local)
                                  DLT_CONNECTION_CLIENT_MSG_SERIAL);
 }
 
-#ifndef DLT_USE_UNIX_SOCKET_IPC
+#ifdef DLT_DAEMON_USE_FIFO_IPC
 static int dlt_daemon_init_fifo(DltDaemonLocal *daemon_local)
 {
     int ret;
@@ -1254,6 +1299,43 @@ static int dlt_daemon_init_fifo(DltDaemonLocal *daemon_local)
 }
 #endif
 
+#ifdef DLT_DAEMON_VSOCK_IPC_ENABLE
+static int dlt_daemon_init_vsock(DltDaemonLocal *daemon_local)
+{
+    int fd;
+    struct sockaddr_vm addr;
+
+    fd = socket(AF_VSOCK, SOCK_STREAM, 0);
+    if (fd == -1) {
+        dlt_vlog(LOG_ERR, "Failed to create VSOCK socket: %s\n", strerror(errno));
+        return -1;
+    }
+
+    memset(&addr, 0, sizeof(addr));
+    addr.svm_family = AF_VSOCK;
+    addr.svm_port = DLT_VSOCK_PORT;
+    addr.svm_cid = VMADDR_CID_ANY;
+
+    if (bind(fd, (struct sockaddr *) &addr, sizeof(addr)) != 0) {
+        dlt_vlog(LOG_ERR, "Failed to bind VSOCK socket: %s\n", strerror(errno));
+        close(fd);
+        return -1;
+    }
+
+    if (listen(fd, 1) != 0) {
+        dlt_vlog(LOG_ERR, "Failed to listen on VSOCK socket: %s\n", strerror(errno));
+        close(fd);
+        return -1;
+    }
+
+    return dlt_connection_create(daemon_local,
+                                 &daemon_local->pEvent,
+                                 fd,
+                                 POLLIN,
+                                 DLT_CONNECTION_APP_CONNECT);
+}
+#endif
+
 int dlt_daemon_local_connection_init(DltDaemon *daemon,
                                      DltDaemonLocal *daemon_local,
                                      int verbose)
@@ -1269,7 +1351,7 @@ int dlt_daemon_local_connection_init(DltDaemon *daemon,
         return -1;
     }
 
-#ifdef DLT_USE_UNIX_SOCKET_IPC
+#ifdef DLT_DAEMON_USE_UNIX_SOCKET_IPC
     /* create and open socket to receive incoming connections from user application
      * socket access permission set to srw-rw-rw- (666) */
     mask = S_IXUSR | S_IXGRP | S_IXOTH;
@@ -1292,7 +1374,7 @@ int dlt_daemon_local_connection_init(DltDaemon *daemon,
         return DLT_RETURN_ERROR;
     }
 
-#else
+#else /* DLT_DAEMON_USE_FIFO_IPC */
 
     if (dlt_daemon_init_fifo(daemon_local)) {
         dlt_log(LOG_ERR, "Unable to initialize fifo.\n");
@@ -1301,6 +1383,13 @@ int dlt_daemon_local_connection_init(DltDaemon *daemon,
 
 #endif
 
+#ifdef DLT_DAEMON_VSOCK_IPC_ENABLE
+    if (dlt_daemon_init_vsock(daemon_local) != 0) {
+        dlt_log(LOG_ERR, "Unable to initialize app VSOCK socket.\n");
+        return DLT_RETURN_ERROR;
+    }
+#endif
+
     /* create and open socket to receive incoming connections from client */
     daemon_local->client_connections = 0;
 
@@ -1484,10 +1573,10 @@ void dlt_daemon_local_cleanup(DltDaemon *daemon, DltDaemonLocal *daemon_local, i
     /* Ignore result */
     dlt_file_free(&(daemon_local->file), daemon_local->flags.vflag);
 
-#ifndef DLT_USE_UNIX_SOCKET_IPC
+#ifdef DLT_DAEMON_USE_FIFO_IPC
     /* Try to delete existing pipe, ignore result of unlink() */
     unlink(daemon_local->flags.daemonFifoName);
-#else
+#else /* DLT_DAEMON_USE_UNIX_SOCKET_IPC */
     /* Try to delete existing pipe, ignore result of unlink() */
     unlink(daemon_local->flags.appSockPath);
 #endif
@@ -1520,7 +1609,7 @@ void dlt_daemon_local_cleanup(DltDaemon *daemon, DltDaemonLocal *daemon_local, i
 void dlt_daemon_exit_trigger()
 {
 
-#ifndef DLT_USE_UNIX_SOCKET_IPC
+#ifdef DLT_DAEMON_USE_FIFO_IPC
     char tmp[DLT_PATH_MAX] = { 0 };
 
     ssize_t n;
@@ -1832,7 +1921,7 @@ int dlt_daemon_process_client_messages(DltDaemon *daemon,
         return -1;
     }
 
-    must_close_socket = dlt_receiver_receive(receiver, DLT_RECEIVE_SOCKET);
+    must_close_socket = dlt_receiver_receive(receiver);
 
     if (must_close_socket < 0) {
         dlt_daemon_close_socket(receiver->fd,
@@ -1908,7 +1997,7 @@ int dlt_daemon_process_client_messages_serial(DltDaemon *daemon,
         return -1;
     }
 
-    if (dlt_receiver_receive(receiver, DLT_RECEIVE_FD) <= 0) {
+    if (dlt_receiver_receive(receiver) <= 0) {
         dlt_log(LOG_WARNING,
                 "dlt_receiver_receive_fd() for messages from serial interface "
                 "failed!\n");
@@ -2010,15 +2099,13 @@ int dlt_daemon_process_control_connect(
     return 0;
 }
 
-#ifdef DLT_USE_UNIX_SOCKET_IPC
+#if defined DLT_DAEMON_USE_UNIX_SOCKET_IPC || defined DLT_DAEMON_VSOCK_IPC_ENABLE
 int dlt_daemon_process_app_connect(
     DltDaemon *daemon,
     DltDaemonLocal *daemon_local,
     DltReceiver *receiver,
     int verbose)
 {
-    socklen_t app_size;
-    struct sockaddr_un app;
     int in_sock = -1;
 
     PRINT_FUNCTION_VERBOSE(verbose);
@@ -2030,10 +2117,9 @@ int dlt_daemon_process_app_connect(
         return DLT_RETURN_WRONG_PARAMETER;
     }
 
-    /* event from UNIX server socket, new connection */
-    app_size = sizeof(app);
+    /* event from server socket, new connection */
 
-    if ((in_sock = accept(receiver->fd, (struct sockaddr *)&app, &app_size)) < 0) {
+    if ((in_sock = accept(receiver->fd, NULL, NULL)) < 0) {
         dlt_vlog(LOG_ERR, "accept() on UNIX socket %d failed: %s\n", receiver->fd, strerror(errno));
         return -1;
     }
@@ -2077,7 +2163,7 @@ int dlt_daemon_process_control_messages(
         return -1;
     }
 
-    if (dlt_receiver_receive(receiver, DLT_RECEIVE_SOCKET) <= 0) {
+    if (dlt_receiver_receive(receiver) <= 0) {
         dlt_daemon_close_socket(receiver->fd,
                                 daemon,
                                 daemon_local,
@@ -2189,28 +2275,21 @@ int dlt_daemon_process_user_messages(DltDaemon *daemon,
         return -1;
     }
 
-#ifdef DLT_USE_UNIX_SOCKET_IPC
-    recv = dlt_receiver_receive(receiver, DLT_RECEIVE_SOCKET);
+    recv = dlt_receiver_receive(receiver);
 
-    if (recv <= 0) {
+    if (recv <= 0 && receiver->type == DLT_RECEIVE_SOCKET) {
         dlt_daemon_close_socket(receiver->fd,
                                 daemon,
                                 daemon_local,
                                 verbose);
         return 0;
     }
-
-#else
-    recv = dlt_receiver_receive(receiver, DLT_RECEIVE_FD);
-
-    if (recv < 0) {
+    else if (recv < 0) {
         dlt_log(LOG_WARNING,
                 "dlt_receiver_receive_fd() for user messages failed!\n");
         return -1;
     }
 
-#endif
-
     /* look through buffer as long as data is in there */
     while ((receiver->bytesRcvd >= min_size) && run_loop) {
         dlt_daemon_process_user_message_func func = NULL;
@@ -2327,6 +2406,7 @@ int dlt_daemon_process_user_message_register_application(DltDaemon *daemon,
     char description[DLT_DAEMON_DESCSIZE + 1] = { '\0' };
     DltUserControlMsgRegisterApplication userapp;
     char *origin;
+    int fd = -1;
 
     PRINT_FUNCTION_VERBOSE(verbose);
 
@@ -2386,11 +2466,14 @@ int dlt_daemon_process_user_message_register_application(DltDaemon *daemon,
     if (old_application != NULL)
         old_pid = old_application->pid;
 
+    if (rec->type == DLT_RECEIVE_SOCKET)
+        fd = rec->fd; /* For sockets, an app specific fd has already been created with accept(). */
+
     application = dlt_daemon_application_add(daemon,
                                              userapp.apid,
                                              userapp.pid,
                                              description,
-                                             rec->fd,
+                                             fd,
                                              daemon->ecuid,
                                              verbose);